Hi,<br>
i want to implement the bridging feature on an arm (cpu intel ixp425), running busybox+linux kernel 2.6.11.<br>
For this, I have recompiled the kernel to enable bridging and ebtables, and I have compiled and installed brctl utility for arm.<br>
<br>
Here is my network setup:<br>
<font DEFANGED_style="background-color: rgb(255, 255, 102); color: rgb(51, 0, 51);" size="1"><span DEFANGED_style="font-family: courier new,monospace; font-weight: bold;"><span DEFANGED_style="text-decoration: underline;"><span DEFANGED_style="text-decoration: underline;">
<span DEFANGED_style="font-weight: bold;">[</span></span>PC_A]</span> eth0 <a href="http://10.0.0.10/24">10.0.0.10/24</a> ======== eth0 ----+----eth1&nbsp; ========&nbsp; <span DEFANGED_style="text-decoration: underline;"><span DEFANGED_style="text-decoration: underline;">
<span DEFANGED_style="font-weight: bold;">[</span></span>PC_B]</span> eth0 <a href="http://10.10.0.1/24">10.10.0.1/24</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
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br0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
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<span DEFANGED_style="text-decoration: underline;"><span DEFANGED_style="text-decoration: underline;"><span DEFANGED_style="font-weight: bold;">[</span></span>ARM]</span>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace; font-weight: bold;">
<span DEFANGED_style="font-family: courier new,monospace;"></span><span DEFANGED_style="font-family: courier new,monospace; font-weight: bold;"></span></font><span DEFANGED_style="font-family: courier new,monospace;"><br>
</span>Here is how I setup my bridge on the ARM:<span DEFANGED_style="font-family: courier new,monospace;"><br>
<font DEFANGED_style="background-color: rgb(255, 255, 102);" size="1">brctl addbr br0<br>
brctl addif br0 eth0<br>
brctl addif br0 eth1<br>
brctl setfd br0 1<br>
ifconfig eth0 promisc<br>
ifconfig eth1 promisc<br>
ifconfig eth0 <a href="http://0.0.0.0">0.0.0.0</a><br>
ifconfig eth1 <a href="http://0.0.0.0">0.0.0.0</a><br>
ifconfig eth0 up<br>
ifconfig eth1 up<br>
ifconfig br0 <a href="http://0.0.0.0">0.0.0.0</a><br>
ifconfig br0 up<br>
ip route add <a href="http://0.0.0.0/0">0.0.0.0/0</a> dev br0<br>
</font><br>
</span><br>
<font size="2">On PC_A, I ping PC_B. It does not work</font><span DEFANGED_style="font-family: courier new,monospace;"><br>
<font DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);" size="1">[pc_a]# ping <a href="http://10.0.0.10">10.0.0.10</a></font><br>
<font size="1"><br>
Then, I verified with tcpdump on the arm platform where the problem could be:<br DEFANGED_style="font-family: courier new,monospace;">
</font></span><font DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);" size="1">[arm]# tcpdump -i br0<br>
listening on br0, link-type EN10MB (Ethernet), capture size 68 bytes<br>
arp who-has <a href="http://10.10.0.1">10.10.0.1</a> tell
<a href="http://10.0.0.10">10.0.0.10</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</font><font DEFANGED_style="background-color: rgb(204, 255, 255);" size="1"><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">3 packets
captured&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">3 packets received by
filter&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">0 packets dropped by
kernel&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span></font><br DEFANGED_style="background-color: rgb(204, 255, 255);">
<br DEFANGED_style="background-color: rgb(204, 255, 255);">
<font DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);" size="1"><span DEFANGED_style="font-family: courier new,monospace;">[arm]# tcpdump -i eth0</span><br DEFANGED_style="font-family: courier new,monospace;">

<span DEFANGED_style="font-family: courier new,monospace;">listening on eth0, link-type EN10MB (Ethernet), capture size 68 bytes</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">arp who-has <a href="http://10.10.0.1">10.10.0.1</a>
tell
<a href="http://10.0.0.10">10.0.0.10</a>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">3 packets
captured&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">3 packets received by
filter&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<span DEFANGED_style="font-family: courier new,monospace;">0 packets dropped by
kernel&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace;">
<br>
</font><br DEFANGED_style="background-color: rgb(204, 255, 255);">
<font DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);" size="1">[arm]#
tcpdump -i
eth1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<br>
listening on eth1, link-type EN10MB (Ethernet), capture size 68 bytes</font><font DEFANGED_style="background-color: rgb(204, 255, 255);" size="1"><br DEFANGED_style="font-family: courier new,monospace;">
</font><font size="1"><span DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);">0
packets
captured&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);">
<span DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);">0
packets received by
filter&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);">
<span DEFANGED_style="font-family: courier new,monospace; background-color: rgb(204, 255, 255);">0
packets dropped by
kernel&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
</span><br DEFANGED_style="background-color: rgb(255, 153, 0); font-family: courier new,monospace;">
</font><br>
The ICMP packet is not sent because the arp resolution is not completed.<br>
Finally, the problem is: why does the bridge not forward the arp request from PC_A (<a href="http://10.0.0.10">10.0.0.10</a>) to PC_B (<a href="http://10.10.0.1">10.10.0.1</a>)<br>
This is a broadcast packet, and it should be forwarded on the other interface of the bridge.<br>
<br>
What I have done to find the problem:<br>
<ul>
  <li>I have verified that both eth0 and eth1 on the bridge are well working in promiscuous mode.</li>
  <li>I have statically defined an arp entry for PC_A inside PC_B, and
an arp entry for PC_B inside PC_A; the result is that the ICMP packet
(ping) is well bridged through the two interfaces of the ARM platform.
Thus the problem is related to the arp resolution.<br>
  </li>
</ul>
<br>
If someone could help me, it would be great because I am completely
locked. Replacing the ARM by a standard PC make the things working.<br>
<br>
--L.Croisez.<br>